Bus rapid transit (BRT) is a term applied to a variety of public transportation systems using buses to provide faster, more efficient service than an ordinary bus line. Often this is achieved by making improvements to existing infrastructure, vehicles and scheduling. The goal of these systems is to approach the service quality of rail transit while still enjoying the cost savings and flexibility of bus transit. The expression BRT is mainly used in North America; in Europe and Australia, it is often called a busway, while elsewhere, it may be called a quality bus.
Bus rapid transit takes part of its name from rail rapid transit, which describes a high-capacity urban public-transit system with its own right-of-way, multiple-car trains at short headways, and longer stop spacing than traditional streetcars and buses. BRT, however, uses buses on a wide variety of rights-of-way, including mixed traffic, dedicated lanes on surface streets, and busways completely separated from traffic.
Typical transit speeds of BRT systems range from 17 to 30 miles per hour (27 to 48 km/h), which can compare with surface running light rail.
BRT systems come in a variety of forms, such as dedicated busways with their own rights-of-way (such as Ottawa's Transitway or Pittsburgh's Martin Luther King Jr. East Busway), bus services using HOV lanes, dedicated freeway lanes (such as Honolulu's CityExpress) and limited stop buses on pre-existing routes.
An ideal bus rapid transit service would be expected to include most of the following features:
- Bus only, grade-separated (or at-grade exclusive) right-of-way: A dedicated bus lane allows the bus to operate separately, without interference from other modes of traffic. Although buses have a long turning radius, busways can be engineered to tighter standards than an open roadway, reducing construction costs while still assuring safe operation.
- A bus-only right-of-way may be elevated or even a modified rail right-of-way.
- A transit mall or bus street can be created into downtown by dedicating all lanes of a city street to the exclusive use of buses.
- Low-cost infrastructure elements that can increase the speed and reliability of bus service include bus turnouts, boarding islands, and curb realignments.
- Comprehensive coverage: BRT systems can also share existing roadways with other traffic or use bus lanes that restrict other traffic from a portion of the roadway. Service along public roadways can be improved by taking advantage of bus priority methods.
- Serves a diverse market with high-frequency all day service: A BRT network with comprehensive coverage can serve a diverse market (all income ranges) by moving large numbers of people between locations quickly and reliably throughout the day, while maintaining a comfortable riding experience. These characteristics are essential to satisfying the demands of a diverse market or offering high-frequency service without heavy subsidy.
- Bus priority: Preferential treatment of buses at intersections can involve the extension of green time or actuation of the green light at signalized intersections upon detection of an approaching bus. Intersection priority can be particularly helpful when implemented in conjunction with bus lanes or bus streets, because general-purpose traffic does not intervene between buses and traffic signals.
- Vehicles with tram-like characteristics
Recent technological developments such as bi-articulated buses and guided buses have benefited the set-up of BRT systems. The main developments are:
- A specific image with a brand name (Viva, Max, TransMilenio, Metropolitano, Select) marking stops and stations as well as the buses. The system's brand identity contributes to its attractiveness as an alternative to driving cars.
- Off-bus fare collection: Conventional on-board fare collection slows the boarding process, particularly when different fares are collected for different destinations and/or classes of passengers. Some systems collect fares upon entering an enclosed bus station or shelter area prior to bus arrivals (similar to fare collection at a kiosk prior to entering a subway system). This allows passengers to board quickly through all doors of a stopped bus.
- Level boarding: Many BRT systems also use low-floor buses (or high-level platforms with high-floor buses) to speed passenger boardings and enhance accessibility.
- Stations: High-quality BRT systems feature significant investment in enclosed stations which may incorporate attractive sliding glass doors, staffed ticket booths, information booths, and other more standard features listed above. This style of station is seen throughout Colombia (Bogotá's TransMilenio, Cali's MIO, Bucaramanga's Metrolinea, Pereira's Megabús) and in most Latin American BRT systems developed in the last decade. The style is also used in Johannesburg's Rea Vaya. The term "station" is more flexibly applied in North America and ranges from enclosed waiting areas (Ottawa, Cleveland), to large open shelters (Los Angeles), to simple signposts.
All of the above characteristics were noted as features of Bogotá's TransMilenio, described as a "model BRT system" in the National Bus Rapid Transit Institute's May 2006 report. TransMilenio serves Bogotá with high-capacity articulated buses, which passengers can board through three doors. Bi-articulated buses are also now used on the busiest routes. A smart card system is used for off-board fare collection. Nevertheless, despite moving 45,000 ppdph, Transmilenio faces huge problems specially during peak hours, in terms of not being quite organized, nor having the necessary capacity for handling the high passenger volume - this situation not being limited to peak hours only, but at most times along the day-.
In cities and large towns, such as Amsterdam, Essen (Germany), Pittsburgh and Seattle, it is common for a right of way exclusive to public transport to be used by both light rail and buses, and in some cases taxis.
Comparison with other forms of mass transit
BRT attempts to combine the advantages of a rail system (noticeably right-of-way, which improves punctuality and frequency) with the advantages of a bus system (low construction and maintenance costs, low vehicle costs, right-of-way not required for entire length, and for the ability of feeder bus services to join a trunk busway). In Latin America and cities in Asia the balance is between metro-quality rail and normally results in consistently similar enclosed stations featuring smartcard turnstiles and level-platform boarding; while in North America the balance is normally between LRT-quality rail and typically results in open air shelters with ticket-dispensers, or even just signposts.
Comparison with conventional bus routes
The dedicated right-of-way lanes of BRT systems allow them an increased average vehicle speed, to provide more passenger miles with the same number of vehicles and personnel than conventional bus services. A smoother ride can also be expected, because the BRT is not immersed in stop-and-go traffic. BRT also features higher frequency service than conventional routes; Latin American systems rely heavily on short headways to achieve their ridership capacity.
But when compared to normal bus service, BRT needs wider roads.
Comparison with light rail
Primary considerations in choosing between light rail and bus rapid transit systems are the differences in construction costs, operating costs, capacity, adaptability and image.
Proponents of light rail point out that the operating costs of BRT are not necessarily lower than light rail. The typically larger light rail vehicles enjoy reduced labor costs and the unit capital cost per passenger can be lower than a BRT system. In contrast to BRT, light rail and tram systems require the placement of rails for the entire line. The tram usually avoids the high additional costs for engineering structures, such as tunnels, that need to be built for metros. Rail tends to provide a smoother ride, making it more attractive to riders than road-based systems.
With similar dwell times in stations, the capacity of rail systems would scale with the length of the train. For instance, a light rail system running on two-minute headways with 200-passenger cars operating as single units could carry 6,000 passengers per hour. Theoretically, it should carry 12,000 passengers per hour with two-car trains, and 24,000 per hour with four-car trains. In practice, real-world delays and headway disruptions cause a practical limitation of around 12,000 to 19,000.
A survey by the UK Transport Research Laboratory reported the following peak passenger flows (passengers per hour) for BRT transitways:
- Designated Lane: Ankara, Istanbul, Abidjan 7,300 – 19,500
- Designated Lanes with Feeders Curitiba, Brazil 13,900 – 24,100
- Designated Lanes with Bus Ordering (Travelling in Clusters) Porto Alegre 17,500 – 18,300
- Designated Lanes with Overlapping Routes, Passing at Stations and Express Routes Belo Horizonte, São Paulo 15,800 - 20,300
- TransMilenio, Bogotá 35,000 - 40,000
Many BRT systems, such as Ottawa's OC Transpo and Brisbane's South-East Busway, are based on multiple bus routes sharing a common dedicated busway to bypass congestion, especially to/from a central business district. In this form, the BRT system's passenger capacity is limited by vehicle capacity multiplied by vehicle headway of the busway. As buses can operate at headways as low as 10 seconds between vehicles (compared to at least one minute headways for rail vehicles), actual busway capacity can reach passenger rail capacities. In the NBRTI's May 2006 report, average headways of 13 seconds at busy intersections were observed in the TransMilenio BRT system.
At the high end, the Lincoln Tunnel XBL bus lane between New Jersey and New York carries 62,000 commuters in the 4-hour morning peak, more than any light rail line. However, this lane has no stops in it. Furthermore, a very large terminal station is required (Port Authority Bus Terminal) to accept and dispatch passengers. Stops increase the headway and limit a BRT lane to about 10,000 passengers per hour, even with passing lanes in the stations. This is still five times the number carried in the automobiles in a congested freeway lane. At its busiest point, Brisbane's South-East Busway currently has the capacity for in excess of 15,000 commuters per hour per direction.
Many agencies make a clear distinction between a pure BRT, which is in exclusive lanes, and a more compromised form in mixed traffic. For example, the Los Angeles Orange Line runs entirely in an exclusive lane and therefore achieves speed and reliability comparable to rail. Because it is functionally equivalent to rail, the Los Angeles County Metropolitan Transportation Authority presents this line as part of its rail transit system, distinct from its "Rapid" lines, which run in mixed traffic.
The capital costs of implementing BRT lines in general is more cost-effective than constructing LRT lines. A study by the United States Government Accountability Office found that the average capital cost per mile for busways was $13.5 million while light rail average costs were $34.8 million. However, a huge range of capital costs exist as BRT lines can cost anywhere from $200,000-$55,000,000 per mile while LRT lines can range from $12.4 million-$118.8 million per mile. Costs vary considerably due to factors such as cost of the roadway, station structures, park-and-ride facilities, traffic signal systems and vehicles.
The typical diesel engine on the bus causes noticeable levels of air pollution, noise and vibration. With hybrid vehicles and the new forms of trolleybus, BRT designers hope to increase ride quality and decrease pollution. As the energy use for acceleration is proportional to the vehicle mass, electric traction allows lighter vehicles, faster acceleration and energy that can be fed back into batteries or the grid through regenerative brakes. Regenerative braking is standard on many modern rail systems.
A BRT system can use trolley-buses to lower gaseous and noise emissions. The price penalty of installing overhead lines could be offset by the system's environmental benefits potential for savings from centrally generated electricity, especially in cities where electricity is less expensive than other power sources. In addition, most trolleybus applications can be converted to light rail with the only extra expense being the laying and maintenance of tram tracks in the street.
In tunnels or tunnel systems
A special issue arises in the use of bus vehicles in metro structures. Since the areas where the demand for an exclusive bus right-of-way is apt to be in dense downtown areas where an above-ground structure may be unacceptable on historic, logistic, or environmental grounds, use of BRT in fully underground tunnels may not be avoidable.
Since buses are usually powered by internal combustion engines, bus metros raise ventilation issues similar to those of tunnels. In the case of tunnels, powerful fans typically exchange air through ventilation structures on the surface, but are usually placed in a location as remote as possible from occupied areas to minimize the effects of noise and concentrated pollution.
A straightforward way to deal with this is to use internal combustion engines with lower emissions. The 2008 Euro V European emission standards set a limit on carbon monoxide from heavy-duty diesel engines of 1.5 g/kWh. This is one third that of the 1992 Euro I standard. As a result, less forced ventilation will be required in tunnels to achieve the same air quality.
A more complex alternative is electrical propulsion in tunnels. Seattle in its Metro Bus Tunnel and Boston in Phase II of its Silver Line are using this method in their BRTs. In the case of Seattle, dual-mode (electric/diesel electric) buses manufactured by Breda were used until 2004, with the center axle driven by electric motors obtaining power from a trolley wire through a trolley pole in the subway, and with the rear axle driven by a conventional diesel powertrain on freeways and streets. Boston is using a similar approach, after initially using electric trolleybuses to provide service pending delivery of the dual-mode vehicles in 2005. In 2004, Seattle replaced its "Transit Tunnel" fleet with diesel-electric hybrid buses, which operate similarly to hybrid cars outside the tunnel and in a low-noise, low-emissions "hush mode" (in which the diesel engine operates but does not exceed idle speed) when underground.
The need to provide electric power in these environments brings the capital and maintenance costs of such routes closer to those of light rail, and raises the question of building light rail instead. In Seattle, the downtown transit tunnel was retrofitted for conversion to a shared hybrid-bus and light-rail facility in preparation for Seattle's Central Link Light Rail line, which opened in July 2009.
Aesthetics of Bus Rapid Transit
Bus rapid transit vehicles, station stops, and collateral elements are typically free of advertising (which is common to many public transit systems). This is not always the case, however: Los Angeles County Metropolitan Transportation Authority (Metro) has video advertising on board the buses.
Think Tanks and Blogs
In the USA there are at least three think-tanks directly involved in lobbying for BRT systems: 1) The National Bus Rapid Transit Institute was established by the US Federal Government in January 1991, and is housed at the Center for Urban Transportation Research (CUTR) at the University of South Florida, and 2) the Bus Rapid Transit Policy Center promotes BRT technology over light rail, and 3) the Institute for Transportation and Development Policy.
The objectivity of the work of CUTR and at least one of its employees has been questioned.
EMBARQ, The World Resources Institute's Center for Sustainable Transport supports the development of BRT and often posts news related to BRT on the TheCityFix blog network.
The Streetsblog.org series of blogs and Streetfilms.org videoblog also are frequent proponents of BRT.
Bus Rapid Transit Planning Guide
In June 2007, the Institute for Transportation and Development Policy (ITDP) published the BRT Planning Guide with support from the United Nations Environment Programme, the Deutsche Gesellschaft für Technische Zusammenarbeit, the Hewlett Foundation, and Viva Cities. The guide, co-authored by Walter Hook of ITDP and Lloyd Wright of Viva Cities, draws from the extensive BRT design experience of Latin American transit planners, and aims to disseminate this information in cities looking to design and implement BRT systems of their own. The guide is currently available in English, Portuguese, and Chinese, and is free for download in .pdf format from ITDP's website.
List of systems
- Main article: List of bus rapid transit systems
Implementation by country
- Main article: Implementation of bus rapid transit by country
- What is Bus Rapid Transit? Select Bus Service website, NY Metropolitan Transit Authority. Retrieved 2010-3-12
- Characteristics of BRT for decision making. page ES-5. Federal Transit Administration (August 2004).
- What is Select Bus Service? NYC Metropolitan Transit Authority. Retrieved 2010-3-12
- Characteristics of BRT for decision making. page ES-8. Federal Transit Administration (August 2004).
- "Applicability of Bogotá's TransMilenio BRT System to the United States" NBRTI (May 2006). Retrieved 2010-03-15.
- Bus Rapid Transit or Quality Bus Reality Check Light Rail Now! (January 22, 2004). Retrieved 2010-03-29
- G. Gardner, J. C. Rutter and F. Kuhn (1994). The performance and potential of light rail transit in developing cities. Project Report No. PR69. Transport Research Laboratory, Crowthorne, UK.
- Characteristics of BRT for decision making. Exhibit 3-22: "Maximum observed peak hour bus flows, capacities, and passenger flows at peak load points on transitways". Federal Transit Administration (August 2004).
- Foro TransMilenio Fase III
- Lord Mayor's Mass Transit Taskforce Report 2007, Brisbane City Council.
- GAO (September 2001). "Bus Rapid Transit Shows Promise". GAO. Retrieved on 2011-03-16.
- Metro Online (December 14, 2007). "Downtown Seattle Transit Tunnel and Changing Bus Technology". King County Metro. Retrieved on 2010-07-13.
- Duncan Allen (2005). "MBTA Silver Line". www.nycsubway.org. Retrieved on 2010-07-13.
- Michael Van Sickler (November 28, 2009). "One of rail's biggest critics gets millions to study and promote alternatives", St. Petersburg Times. Retrieved on 2010-03-10. .
- "Planning Guide for Bus Rapid Transit Published". Institution for Transportation & Development Policy (June 16, 2007).
- Complete BRT Planning Guide (English) ITDP (June 2007).
- The National BRT Institute
- BRT Technologies: Assisting Drivers Operating Buses on Road Shoulders. University of Minnesota Center for Transportation Studies, Department of Mechanical Engineering (December 2003).
- Bus Rapid Transit Policy Center
- Bus Rapid Transit Planning Guide (available for download in pdf) Institute for Transportation & Development Policy
- Institute for Transportation and Development Policy
- Across Latitudes and Cultures Bus Rapid Transit An international Centre of Excellence for BRT development
- "Bus Rapid Transit Shows Promise" U.S. General Accounting Office
- Wang Fengwu and James Wang (April 2004). "BRT in China". Public Transport International. Retrieved on 2010-03-10.
- Bus Rapid Transit, Volume 1: Case Studies in Bus Rapid Transit Transportation Research Board
- Bus Rapid Transit, Volume 2: Implementation Guidelines Transportation Research Board
- Transit Capacity and Quality of Service Manual Transportation Research Board
- Delhi BRT System Delhi Transit.
- Bus Priority Systems, a web page about the guided busway system, including its use underground in Essen, Germany.
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